\begin{tikzpicture}[>=Stealth, scale=0.6]
    \draw [->] (-6.5, 0) -- (6.5, 0);

    \draw (0, 0) node[below] {$O$};
    \foreach \x in {-3, ..., 3} {
        \draw (\x, 0.2) -- (\x, 0);
    }

    \pic [transform shape] {interval={start=-3, stop=-6, height=0.5, infinity=true}};
    \pic [transform shape] {interval={start= 3, stop= 6, height=0.5, infinity=true}};
    \foreach \x in {-3, 3} {
        \draw [fill=white] (\x, 0) circle(0.1) node [below=0.2em] {$\x$};
    }
\end{tikzpicture}

